What is Biodiversity

Updated on July 1, 2011

Biodiversity

Meaning of Biodiversity

The term ‘Biodiversity’ refers to the variety of all life on
earth and its myriad of processes. It includes all life forms – from the
unicellular fungi, protozoa and bacteria to complex multicellular organisms
such as plants, birds, fishes and mammals. Biodiversity helps in providing the
basic human needs such as food, shelter and medicine. It composes ecosystems
that maintain oxygen in the air, purify the water, enrich the soil, protect
against flood and storm damage, and regulates climate.

The term ‘biodiversity’ gained immediate acceptance and was
brought to popular attention by the world media during the Earth Summit in Rio de
Janeiro in the year 1992. The final text of the Global
convention on Biological Diversity (1992) defined it as follows:

"Biological diversity
is the variability among living organisms from all sources including
terrestrial, marine and other aquatic ecosystems and the ecological complexes
of which they are a part; this includes diversity within and of ecosystems.”

Types of Biodiversity

Biodiversity manifests itself at three levels:

Species diversity – The richness
of species in an ecosystem is called as ‘species diversity’. It refers to
the number and kinds of living organisms at a particular place. Species
are the basic and important units in modern systems for classifying living
organisms. The number of species on earth is very large and no one knows
the exact number of species because new species are being discovered all
the time, especially in little explored areas such as tropical forests and
the deep oceans.

Genetic diversity – Within any
given species, there can be several varieties, strains or races which
slightly differ from each other in one or more characteristics such as
size, shape, resistance against diseases, etc., and resilience to survive
under adverse environmental conditions. Such diversity in the genetic
make-up of a species is termed as the ‘genetic diversity.’ The species
having large number of varieties, strains or races are considered as rich
and more diverse in its genetic organization.

Ecosystem
diversity – ‘Ecosystem diversity’ is generally assessed
in terms of the global or continental distribution of broadly-defined ecosystem
types, or in terms of the species diversity within ecosystems. Ecosystems assessed
in terms of the diversity of species may include estimation of richness in
particular groups and evaluation of their relative abundance. A system having
the component species present in nearly equal abundance is considered as more
diverse than one having extremes of high and low abundance.

Biodiversity is a valuable genetic resource as most
of the hybrid varieties of crops under cultivation have been developed by
incorporating useful genes from different species of plants to produce better
quality of the product.